This invention relates generally to devices having ad hoc networking capability, and more particularly to information exchanged between such devices within piconets.
There has been much promotion of devices that include ad hoc networking capability. Ad hoc networks are rapidly deployable, and function without infrastructure support. An ad hoc network is one in which the devices can communicate with each other as they come within range of each other, without prior networking setup. Devices can join and leave an ad hoc network on an ongoing basis. When there is only one device left, the ad hoc network dissipates as quickly as it was created.
An example of an ad hoc network is a laptop computer that has ad hoc networking capability sending a document to a printer that has also ad hoc networking capability. Once the laptop computer has moved within range of the printer, the ad hoc network comes into existence. The computer can print documents on the printer, and when it moves out of range, the network ceases to exist.
Ad hoc networks are enabled by specific communication hardware. One type of such hardware is known as Bluetooth. Bluetooth connectivity enables devices that have this type of hardware to create ad hoc networks with other devices that have Bluetooth connectivity. The range of Bluetooth-enabled devices is quite limited, and is measured by tens of feet. Another type of such hardware is known as the 802.11b standard. Unlike Bluetooth, 802.11b-enabled devices have a longer range, which is measured by hundreds of feet.
Ad hoc networks can be more specifically divided into two categories: piconets, and scatternets. All the devices within a piconet are within range of one another. For example, if there are three devices in a given piconet, the first device can directly communicate with the second and third devices. Likewise, the second device can directly communicate with the first and third devices, and the third device can directly communicate with the first and second devices.
Scatternets, on the other hand, are made up of two or more piconets with at least one device in common. For example, the devices within one piconet communicate with the devices within another piconet through one of the intermediary devices in common with both piconets. There may be a first piconet with a first device and a second device, and a second piconet with the second device and a third device. The first device can only communicate with the third device through the second piconet, because the first device is not within the range of the third device. This communication methodology is known as store and forward, where information is communicated over multiple hops.
A disadvantage to current ad hoc networking implementations is that information can only be exchanged among devices where a piconet or a scatternet is currently in existence. For example, there may be four devices. If the first device comes into range with the second device at the same time the second device is in range with the third device, then the first device can communicate with the second device through a piconet and with the third device through a scatternet. However, even if the second device had earlier been in a piconet with the fourth device, which has since moved out of range, the first device cannot receive information from the fourth device. Because the fourth device is not simultaneously in a piconet or a scatternet with the first device, the first device cannot exchange information with the fourth device.
For this and other reasons, therefore, there is a need for the present invention.